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Calculators / RF Link Budget
RF Link Budget
Calculator
Complete end-to-end RF link budget: EIRP → free-space path loss → received power → SNR → link margin. Essential for wireless communication system design, satellite link analysis, and RF system planning. Full waterfall budget breakdown.
TX (EIRP)
Path Loss
RX / Margin
⚙ Link Budget Engine
📡 Transmitter
20 dBm = 100 mW
dBi
0 dBi = isotropic. Half-wave dipole = 2.15 dBi
dB
EIRP = Pt + Gt − cable = —
dB
Antenna beam misalignment loss
📶 Propagation
λ = — cm
Free-space link distance
Total atm loss = rate × distance
📻 Receiver
dBi
0 dBi = isotropic. High-gain dish: 30–50 dBi.
dB
Coax run from antenna to receiver
dBm
Minimum detectable signal level
dB
LNA: 2–4 dB, typical receiver: 6–10 dB
Advanced / SNR Parameters
MHz
Used for thermal noise floor calculation
Minimum Eb/N0 for target BER
dB
Hardware non-idealities, modem imperfections
dB
Design target fade margin (typical: 10–20 dB)
Link Budget Summary
Link Margin
—dB
−20 dB0+10+20+40 dB
Received Power (Pr)—
EIRP—
FSPL—
SNR at RX—
Total path loss—
Thermal noise floor—
Max range (at margin=0)—
Link status—
Enter parameters above to calculate.
Complete Link Budget Waterfall
| # | Parameter | Value (dB) | Running Total (dBm) | Note |
|---|---|---|---|---|
| Enter values above to generate budget | ||||
📖 Theory
A link budget is an accounting of all gains and losses in an RF communication system from the transmitter output to the receiver decision circuit.
Budget Equation
Pr = Pt + Gt − L_t − FSPL − L_atm − L_pol + Gr − L_r
All in dB/dBm. Every gain adds, every loss subtracts.
Link Margin
M = Pr − S
M = Pr − (N₀ + NF + BW + Req_SNR)
M > 0 → link works. Design for M ≥ 10–20 dB.
FSPL Formula
FSPL(dB) = 20·log(d_km) + 20·log(f_GHz) + 92.44
📊 Received Power & Margin Viewer
Live Charts
|
◉ Pr vs distance — sensitivity threshold shown
View
Max Distance
100 km
TX Power
20 dBm
Received Power (dBm) vs Distance
ℹ
Link Budget Insights
Enter link parameters to see system design insights.
Common Applications
Wireless Communication
Design WiFi, cellular, LoRa, ZigBee, and Bluetooth links. Determine maximum range and required antenna gain for a given link margin.
Satellite Links
LEO, MEO, and GEO satellite uplink/downlink budgets. Calculate EIRP, G/T, and C/N₀ for earth station and spacecraft design.
RF System Planning
Network coverage planning, base station siting, repeater spacing, and spectrum efficiency analysis for licensed and unlicensed bands.
Research & Education
Teach and study wireless propagation, link margin concepts, modulation-SNR requirements, and noise figure effects on system performance.
Get "10 RF Design Principles Every Engineer Should Know" Free
Learn practical principles for better RF circuits, PCB layouts, simulations, measurements, and troubleshooting.